If you're already using the application, you can join here: Join!
If you haven't registered, you can sign up for an account here: Register and Download it on any (or all!) of your platform(s) of choice (web interface, Windows, Mac, iOS or Android).

This is in addition to not in place of our current IRC server. You are still more than welcome to join IRC (here) and hang out with us there, or use both, or use neither and just keep putting up comments!